以水 熱法製備鈷/錳氧化物電極及其電容特性探討之研究

Abstract

In the present study, the preparation of Co/Mn (cobalt/manganese) oxide electrode was mainly based on three steps. First, Co-oxide nanostructure was prepared on a graphite substrate by hydrothermal process as a function of hydrothermal time. Experimental results showed that the hydrothermal synthesized Co-oxide exhibited a snowflake-like morphology with a hierarchical structure. Second, the snowflake-like Co-oxide was post heated at 300°C and 350°C in an ambient atmosphere. Subsequently, the Mn-oxide was deposited onto the surface of the Co-oxide nanostructure to form a Co/Mn oxide core-shell structure by a secondary hydrothermal process. The resulting Co/Mn oxide core-shell structures were characterized using XRD, SEM, TEM, XPS and electrochemical analyses. The effect of post heat treatment on the material characteristics and pseudocapacitive performance of the core-shell structure were investigated. The dimension of hydrothermal synthesized Co-oxide with a snowflake-like morphology varied with the post heat treatment conditions. The Co-oxide nanostructure served as a template for the growth of Mn-oxide films. A highest specific capacitance (SC) of 196 F/g and a relatively good electrochemical reversibility can be obtained when the composite electrode was calcined at 300oC for 4 h. More than 90% capacitance retained after 1200 CV (cyclic voltammetry) cycles. The Co/Mn oxide core/shell structure exhibited a better electrochemical stability, being one of the promising active materials in pseudocapacitor applications.